-a-thon
Usage notes
While the suffix -athon may or may not be set off by a hyphen (both dance-athon and danceathon can be found), -a-thon is always set off by a hyphen: one sees dance-a-thon, not *dancea-thon.
While the suffix -athon may or may not be set off by a hyphen (both dance-athon and danceathon can be found), -a-thon is always set off by a hyphen: one sees dance-a-thon, not *dancea-thon.